Locking device for pump impellers



Aug. 6, 1935.

Q A. L. McHUGH 2,010,525

LOCKING DEVICE FOR PUMP IMPELLERS Filed Feb. 26, 1934 H15 ATTORNEY Patented Aug. 6, 1935 PATENT OFFICE LOCKING DEVICE FOR PUMP IIMPELLEBS Anthony L. McHugh,

Easton, Pa., assignor to Ingersoll-Rand Company, Jersey City, N. J., a corporation of New Jersey Application February 26, 1934, Serial No. 712,998

3 Claims.

This invention relates to locking devices, and more particularly to a locking device for securing an impeller to a pump shaft.

One object of the invention is to facilitate the 5 operations of disposing the impeller upon the pump shaft and removing it therefrom, and

Another object is to protect the securing means against exposure to liquid and consequent adherence thereof to the shaft or the impeller through corrosion.

Other objects will be in part obvious and. in part pointed out hereinafter.

In the drawing accompanying this specification and in which similar reference numerals refer to similar parts,

Figure 1 is a longitudinal sectional elevation of a centrifugal pump having its impeller secured to the shaft by a device constructed in accordance with the practice of the invention,

Figure 2 is an enlarged view of fragmentary portions of the impeller and shaft showing these elements drawn together and secured in operative relationship,

Figure 3 is a view similar to Figure 2 showing the manner in which the impeller may be removed from the shaft, and

Figure 4 is a longitudinal side view of a detail.

Referring more particularly to the drawing, I designates in general a pump of the centrifugal type comprising a casing I I which is supported by a base plate I2 and secured thereto by bolts I3.

Closures are provided for the ends of the casing II in the form of heads I4 and I5 which, together with the casing II, define a pumping chamber I6 for the accommodation of an impeller II whereby liquid, flowing to the pumping chamber I6 through an inlet connection I8 carried by the head I5, is pumped through a discharge pipe I9 to a desired destination.

The impeller Il may, as shown, be of the single open type. It is mounted on the extremity of a shaft '20 extending through the head I4 and, in the present instance, through a bushing or wearing sleeve 2| which is journalled in the head I4 to provide a renewable wearing surface for the shaft 20. The shaft is secured to the sleeve 2| by a key 22, and in the head I4 is a stufling box 23 for the accommodation of packing material 24 which is compressed into sealing relationship with the sleeve 2| by a gland 25.

In accordance with the practice of the invention, a recess 25 is formed in the hub 21 of the impeller II to receive the end of the shaft 20. In the peripheral surfaces of the recess 26 and the shaft 20 are slots 28 and 29, respectively, for the reception of a key 30 whereby the impeller is locked against rotary movement with respect to the shaft 20.

Leading from the bottom of the recess 26 and extending outwardly through the hub 21 is a 5 threaded aperture 3| of which the threads may be considered, for the purpose of this invention, as extending in a left hand direction. The aperture 31 is arranged coaxially with a threaded aperture 32 in the end of the shaft 20 and the threads of said aperture 32 extend in an opposite hand direction to and are of the same pitch and diameter as those of the aperture 3|.

In order to effect longitudinal movement of the impeller II with respect to the shaft 20, either for drawing the impeller into its assembled position on the shaft or to withdraw the impeller from the shaft, a screw 33-having its ends threaded in opposite hand directions for cooperation with the threads of the apertures 3| and 32 is threaded into said apertures by a suitable implement, as for instance a wrench 34, which may engage a socket 35 in the end of the screw 33.

To the end that liquid may be excluded from the apertures 3| and 32 as well as the recess 26 the outer end of an opening 36 leading from the aperture 3| to the surface of the impeller is provided with a tapered thread 31 for the accommodation of a pipe plug 38 which seals the recesses within the impeller and the shaft at this point. The plug 38, moreover, serves as a seat for an end of a spring 39 which seats with its opposite end against the screw 33 to prevent unthreading of the screw.

In practice, whenever it is intended to place an impeller upon the end of the shaft 20 the impeller is so positioned on the shaft as to assure registry of the slots 28 and 29 and the key 30 is then entered in the slots. The screw 33, which is first partially threaded into one of the apertures, as for instance that designated 32, is then rotated in a clockwise direction for drawing the impeller onto the shaft 20 or, more particularly, to a position wherein the end face of the hub 21 seats against the adjacent end of the sleeve 2|, thus effecting a seal between the slot and the sleeve to prevent the entrance of liquid into the apertures in the shaft and the impeller. .After the impeller is firmly secured to the shaft the plug 38 is screwed into the outer end of the opening 36 to seal said opening and to compress the spring 39.

In order to remove the impeller from the shaft 20 the plug 38 and spring 39 are first removed. The screw 33 is then rotated in a counter clock- 55 wise direction. Rotation of the screw in this direction causes the impeller to be withdrawn from the end of the shaft.

As will be readily apparent from theforego- 5 ing description, the portions of the impeller and the shaft wherewith the screw 33 cooperates for securing the impeller to the shaft will, at all times,

be adequately isolated from the liquid being pumped and will, therefore, be protected against and extending part way through each, key means for preventing rotary movement of the impeller with respect to the shaft, and a screw having opposite hand threads engaging the threads of the apertures to eifect longitudinal movement of the impeller with respect to the shaft upon rotation of the screw, there being an opening in the impeller to admit access to the screw, and means for sealing said opening.

2. In combination, a pump having a shaft, an impeller having a recess to receive the end of the shaft, there being threaded apertures in the shaft 'and the impeller, key means for preventing rotary shaft, there being threaded apertures in the shaft and the impeller, key means for preventing rotary movement of the impeller with respect to the shaft, a screw having opposite hand threads of the same pitch and diameter cooperating with the threads of the apertures for actuating the impeller longitudinally of the shaft, a closure in the aperture in the impeller to prevent the entrance of liquid into the apertures and the recess, and a spring interposed between the closure and the screw to prevent unthreading of the screw.

ANTHONY L. MCHUGH. 

